Effect of the tannoid enriched fraction of Emblica officinalis on α-crystallin chaperone activity under hyperglycemic conditions in lens organ culture

Abstract

P. Anil Kumar, P. Yadagiri Reddy, P. Suryanarayana and G. Bhanuprakash Reddy*

Chaperone-like activity (CLA) of α-crystallin is known to be compromised in diabetic conditions and associated with cataract formation. Protecting α-crystallin CLA may help in delaying and/or preventing cataracts. In this study, we employed a lens organ culture model to study the effect of hyperglycemia on the CLA of α-crystallin and investigated the protective effect the tannoids of Emblica officinalis had on the CLA of α-crystallin. Goat lenses were treated with 30 mM glucose with or without an aqueous extract of E. officinalis tannoids (25 or 50 μg/ml) for 12 days. Cataract development due to hyperglycemia was monitored and a lens soluble protein profile was analyzed using HPLC. α-crystallin fractions from cultured lenses were isolated by gel filtration; CLA, hydrophobicity and structural confirmation of αcrystallin were assessed using light scattering methods. Culturing the lenses with 30 mM glucose resulted in the development of cortical cataracts and the formation of high molecular weight aggregates. α-crystallin isolated from lens incubated in hyperglycemic conditions displayed a significant decrease in CLA. Co-culturing lenses with glucose and tannoids normalized the altered crystallin profile, preserved α-crystallin CLA and prevented cataract formation. This suggests that tannoids may mitigate hyperglycemia mediated manifestations to α-crystallin thereby preventing cataract formation. Tannoids of E. officinalis prevented the loss of α-crystallin CLA and cataract formation in lens organ culture. Thus, lens organ culture can be employed to investigate the pharmacological potential of compounds that modulate α-crystallin CLA and consequently delay or prevent cataractogenesis.